The present invention relates to an image forming apparatus, such as a complex-type digital copying machine that can be provided with option units, an example of which is a finisher.
There is a conventional digital copying machine that can be provided with option units, an example of which is a finisher. In this type of digital copying machine, the operation of the main body of the digital copying machine is controlled in accordance with the processing speed of the finisher. For example, at the start of a copying operation, the main body of the digital copying machine is made to stand by until the end of the operation of the finisher, such as the operation of initialization or the operation of changing the sheet discharge bin position for use in the copying process. In the standby state, the main motor (drum motor) and other motors employed in the main body of the digital copying machine are kept rotating.
If the print start request that uses a different sheet discharge bin from the one used last is made (i.e., when the copy button is depressed, the printer-mode printing is requested, the facsimile-mode printing is requested, or the like), the conventional digital copying machine to which the finisher is connected first rotates the motors, including the main motor, and then requests that the finisher move the sheet discharge bins.
As can be seen from this, movement of the bins of the finisher is started when the motors are rotating. A sheet supplied from a sheet feed cassette is made to stop immediately in front of the register rollers and waits for the finisher to complete the movement of the bins. Thereafter, the sheet is fed to the image formation section. While the sheet is waiting for the completion of the bin movement, the motors keep rotating in an idle manner.
When printing operations are executed successively, there may be a new print request, and this printing will uses a different sheet discharge bin from the presently used one. Even in this case, the bins are moved, with the motors rotating. The supplied sheet waits for the completion of the bin movement immediately in front of the register rollers, and is then fed to the image formation section.
When the bin presently in use becomes replete with stacked sheets, the sheet discharge bins are moved. In this case as well, the bins are moved, with the motors rotating in the idle manner. That is, the supplied sheet waits for the completion of the bin movement in front of the register rollers, and is then fed to the image formation section.
In the case where the bin moving distance of the finisher is long or the bin moving speed is low, the time required for the bin movement is inevitably long. Hence, the motors of the main body of the digital copying machine have to rotate in the idle manner. This being so, consumables driven by the motors, such as a photosensitive drum, deteriorate in a short period of time.